Effect of Parameters on Treatment of Industrial Effluents Using Inverse Fluidized Bed Bioreactor: Statistical Analysis

Abstract

Phenolic wastewater (effluents from steel plant) was treated in an inverse fluidized bed (IFB) bioreactor. Effects of different system parameters (viz. residence time (t), settled bed to bioreactor volume ratio (Vb/Vr), water flow rate, static bed height, and gas flow rate) on removal of chemical oxygen demand (COD) were studied to determine the optimum conditions. Optimal conditions corresponding to the largest COD removal were obtained at Vb/Vr ratio of 0.55 and gas flow of 40 LPH with time period greater than 62 h. COD removal was also measured with the addition of mineral salts in the wastewater. The results thus obtained with and without the addition of mineral salt to the wastewater were compared. Addition of nutrient salts to the wastewater yielded better percentage of COD removal. The effect of different types of salts on COD removal was also studied with respect to the biomass growth. Experiments were also carried out by continuous culturing of biomass samples. Conversions greater than 68% and 84% were achieved with batch and continuous mode operation respectively, implying that IFB bioreactor can be used successfully for the treatment of industrial effluents.